Perma - it is very tempting to slip this one into the huge CRM arena, but I think it more important to re-emphsise the almost forgotten words "basic airmanship" as Boeing have had to. I expect they were 'too busy' at the time of the GPWS Gear warning to run through anything approaching DODAR, which has its place but really would call for a g/a to diagnose that one properly.
I do, of course, support your last sentance.
TP - I suspect it was just one of those 'wiggly amps/straight volt' things - I think from fading memory the ground reading is -4 and it MAY be that the 'dormant' reading is -8? Who knows?